An ultra-broadband photonic-chip-based parametric amplifier

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Semiconductor Devices

Background:

• Optical amplification is vital for modern communication, with erbium-doped fibre amplifiers (EDFAs) being the primary technology.
• EDFAs have limited spectral coverage, necessitating amplifiers beyond the erbium gain window.
• Optical parametric amplifiers (OPAs) offer potential but face challenges with power requirements and bandwidth limitations in existing platforms.

Purpose of the Study:

• To develop an ultra-broadband, high-gain optical amplifier using integrated photonic circuits.
• To overcome the bandwidth limitations of previous on-chip OPAs.
• To demonstrate a compact and efficient amplification solution for coherent communication signals.

Main Methods:

• Utilized low-loss gallium phosphide-on-silicon dioxide photonic integrated circuits (PICs).
• Engineered compact waveguides (centimeters long) to enhance mode confinement and optical nonlinearity.
• Characterized parametric gain, bandwidth, dynamic range, and noise figure of the developed OPA.

Main Results:

• Achieved up to 35 dB of parametric gain in centimeter-long waveguides.
• Demonstrated fibre-to-fibre net gain exceeding 10 dB across an ultra-broad bandwidth of approximately 140 nm (17 THz).
• Showcased a high dynamic range (six orders of magnitude) and low noise figure, enabling amplification of coherent communication signals.

Conclusions:

• This work presents the first ultra-broadband, high-gain, continuous-wave amplification on a photonic chip.
• The developed gallium phosphide-based OPAs offer a threefold increase in gain window compared to C-band EDFAs.
• These findings open new capabilities for next-generation integrated photonics and telecommunications.